Stridor
It is a high pitched, harsh sound resulting from turbulent gas flow in the upper airway caused by partial airway obstruction. It can be typically heard on inspiration, but it appears also on expiration or on both phases of breathing. Inspiratory stridor suggests an obstruction above the glottis, due to collapse of soft tissues of the throat. Expiratory stridor indicates an obstruction in the lower parts of trachea and bronchi. Biphasic stridor can indicate edema near the cricoid cartilage that surrounds the trachea. Stridor is usually indicative of serious airway obstruction or a potential medical emergency and should always command attention.
